o_1977r8vv9vk1ts2ms0kd8pksa.pdf

520 W. J. Ott
Table 35.1. Causes of heart failure: comparison of adult
and fetal causes
Cause Adult Fetus
Cardiac arrhythmia Disorders of
arrhythmia
Decreased
contractility
Metabolic
disorders
Anoxia/ischemia
Myocarditis
Cardiac anomalies Congenital or
acquired
Increased peripheral
demand
Increased
afterload
Increased preload
Decreased venous
return
Myocarditis
Systemic infection
Anemia
AVshunts
Hypertension
Valvular stenosis
Valvular
regurgitation
Hemorrhage
Vena cava obstruction
Congenital
arrhythmias
Maternal collagen
vascular disease
Maternal
ketoacidosis
Intrauterine
growth restriction
Myocarditis
Congenital
anomalies
Myocarditis
Chorioamnionitis
Systemic infection
Anemia
Fetal tumors
Chorioangioma
Uteroplacental
insufficiency?
Congenital heart
disease
Recipient twin
Indomethacin?
Hemorrhage
(abruption, vasa
previa, fetomaternal,
other)
Venous obstruction
(tumor,
hydrops, other)
Iatrogenic Drug effects Indomethacin,
tocolytics, others
eral venous pressure and fetal decompensation and
cardiac failure. Table 35.1 compares the causes of cardiac
failure in the adult with known or postulated
causes in the fetus.
The Scope of Fetal Cardiac Failure
Changes in obstetrical management, the development
of new and more accurate methods of fetal surveillance,
and a better understanding of the pathogenesis
of fetal demise has led to changes in the distribution
of the causes of stillbirths. Table 35.2 shows the distribution
of stillbirths from a review at the author's
institution for the years 1988 through 1992. There
were four fetal deaths directly caused by fetal heart
failure: one premature closure of the foramen ovale;
one case of non-immune hydrops caused by tachyarrhythmia;
one case of significant increase in cardiac
afterload caused by prune-belly syndrome; and one
case of myocardial hypertrophy with heart failure in
Table 35.2. Causes of fetal death: SJMMC Stillbirths 1988±
1992
Category Number Percentage (%)
Placental
Abruption 13 9
Other 27 a 17
Infection 32 b 21
Anomalies 19 13
Twin complications
Mono/Mono 3 c 2
Twin±twin transfusion 10 d 6
Unknown 2 1
Cord accident
Nuchal 7 5
True knot 2 1
Vasa previa 1 1
Fetal heart failure 4 3
Maternal
Liver rupture 2 1
Ketoacidosis 1 1
Aortic aneurysm 1 1
Unknown 27 18
Fetal trauma: ± ±
Rh: ± ±
Total 151 100
a Includes two sets of twins with three stillbirths.
b Includes one set of twins with two stillbirths.
c Two sets of twins with one survivor.
d Includes one set of triplets with a single survivor.
a fetus of a diabetic mother. Although only 3% of fetal
deaths were directly caused by fetal heart failure,
it most likely played a significant role in many other
fetal deaths: heart failure was the most likely terminal
event in the cases of intrauterine infection (21%),
twin±twin transfusion (6%), cord accidents (7%), and
acute maternal problems (3%); and may have play a
role in many of the cases of placental failure (17%). It
is, therefore, likely that fetal heart failure plays a significant
role in at least 40%±50% of stillbirths.
Duplex Doppler Evaluation
of the Fetal Cardiovascular System
Evaluation of fetal cardiac status includes measurements
of velocity parameters in both peripheral vessels
and the heart itself. In peripheral vessels angleindependent
indices, such as the pulsatility index, resistance
index, and systolic/diastolic (S/D) ratio, are
most commonly used. The peripheral vessel most
commonly evaluated is the umbilical artery. Changes
in the velocity indices in this vessel reflect alterations
in placental perfusion that may precede evidence of
heart failure in situations of uteroplacental insufficiency.
Additional peripheral fetal vessels, such as the
aorta, renal arteries, and carotid and middle cerebral